Annealing furnace



March 27, 1951 iled Nov. 4, 1948 T. W. MUNFORD ANNEALING FURNACE 2 Sheets-Sheet l JINVENTOR.

A TTOP/VEY March 27, 11951 T. w. MUNFORD 2,546,697

ANNEALING FURNACE iled Nov. 4, 8 2 Sheets-Sheet 2 FIG.

INVENTOR. [W Mumford A TTOFP/VE Y Patented Mar. 27, 1951 UNITED STA? ANNEALING FURNACE Application November 4, 1948, Serial No. 58,216

2 Claims.

Coiled sheet metal is customarily annealed under a bell type cover so that a protective atmosphere may be maintained about the metal during the annealing operation. The cover is tall enough to accommodate a stack of coils and the stand or base on which the stack is supported comprises a refractory pad or pedestal on the furnace base. The sides of the pedestal are commonly protected by a metal sheath or band and the top by a metal plate. However, the incidents of placing the coils on the stand and building up of the stack are such that it is practically impossible to avoid doing some damage to the edge of the pedestal with consequent spalling of the edges. These spalled particles tend to crowd into the space between the sides of the pedestal and the encircling sheath as thermal expansion of the sheath permits with the result that radial stress is applied to the inner side of the sheath on cooling. Moreover,

as a result of repeated heating and cooling ver type of sheath or band about the pedestal and,

to provide other related improvements for increasing the life of the coil supporting stand.

For a consideration of what I consider to be novel and my invention attention is directed to the following specification and the claims appended thereto.

In the drawings forming part of this specification- Fig. 1 is a vertical sectional view of the base portion of a furnace embodying the present invention with parts of the upper portion of the furnace omitted.

Fig. 2 is a partial plan. and sectional view of the stand portion of the furnace.

Figs. 3 and 4 are enlarged fragmentary detail views.

The furnace comprises a base it and a bell type heating hood l removably seated on the base (in the drawing the roof or top portion of the heating hood has been omitted). A sub stantially gas-tight seal is maintained between a the base i ii and hood by means of sand i2 about depending sealing blades l3 carried by the hood.

The furnace base is provided with a coil-supporting stand whereon a stack of coils M to be annealed may be supported, the stack being covered by a metal cover 25 to permit a proective atmosphere to be maintained about the coils during the annealing operation. The stand comprises a metal plate It whereon the coil stack is seated, a plurality of pillars l? whereon the plate it is removably seated, a metal plate 25 whereon the pillars ii are removably seated, a refractory body 2! in the form of a pedestal whereon the plate 2b is seated, the said refractory body constituting an integral part of the furnace base ID.

The bottom portion of the furnace base it! comprises a sheet metal floor 22 on supporting beams 23. The floor 22 supports a layer 2% of heat insulating concrete which in turn sup ports a refractory concrete floor 25. The pedes tal Z! is part of the floor 25 and is poured at the same time as the latter. The refractory floor 25 has a trough 25 around the pedestal 2| for granular sealing material 28 about the foot of the protective cover l5. Several plate-type supports 21 mounted on the metal floor 22 under the foot of the protective cover it transmit the weight of the latter to the underlying supporting structure of the furnace base.

Means not shown but carried by the hood H heat the inner cover l5 which in turn heats the coils It to be annealed. Rapid heating of the coils is promoted by circulating the protective atmosphere through and about the coils and this circulation is produced by a power driven fan 3% mounted on a vertical drive shaft 3! driven by an electric motor 32 suspended from the underside of the furnace base IQ. The fan is located in a short vertical duct 33 supported on and integral with a plurality of underlying supporting fingers 34 which rest on a reinforcing plate 35 on the metal floor 22, this reinforcing plate providing a suitable overhead support for the electric motor 32. The atmosphere circulated by the fan 36 flows laterally below the top plate E6 of the coil stand through passage between the supporting pillars H, the pillars rising from segmental bases 36 which rest on the wear plate 26.

In the present invention the refractory pedestal 2! is surrounded by a vertically corrugated metal wall or band 3%, this band initially constituting form whereinto refractory concrete is poured to form the pedestal, hence the side 3 surface of the pedestal is vertically corrugated in conformity with the corrugations of said hand. The lower edge of the band is supported on spacers st conveniently formed as radial extensions of the several underlying supports 2? for the protective cover l5.

As already explained, the incidents of placing the sheet metal coils it on the coil-supported stand and of building up the stash of coils are usually such that it is practically impossible to avoid doing some damage to the top edge of the refractory pedestal at least to the extent of causing spalling of said edge. These spelled particles tend to crowd into the space between the band and the pedestal as thermal expansion of the hand permits and thus set up radial stress in the band during cooling, tending to cause distortion of the band on repeated heating and cooling. Moreover vertical cracks tend to 1 velop in the bod of the refractory pedestal a result of repeated heating and cooling and sand entering these cracks tends to prevent closing of the cracks during cooling with the result that the band around the pedestal is under radial stress from this cause also. However, in the present invention the transverse corrugations in the band permits stretching or yielding of the band under radial stress without destructive distortion with the result that vertically corrugated band has a substantially longer life than a flat metal band.

The foot or lower portion of the band is embedded. in the underlying concrete of the floor 25 and may if desired be extended down to the metal floor 2.2 so that load imposed on the band from above may be transmitted direct to the underlying supporting structure of the furnace base. The upper edge of the band is welded at its crests, as indicated at ll, to the underside of the projecting edge of the Wear plate 2% whereby the trough portion of the band is free to move with respect to said plate, as under thermal expansion.

From the foregoing description it will now be understood that the use of a vertically or transversely corrugated band about the refractory pedestal of the coil supporting stand may be said to constitute the crux of the present invention.

What I claim is:

1. A charge support for a furnace base comprising a generally circular refractory pedestal on the base, a metal band surrounding and embracing the pedestal to form a protective outside wall therefor, said pedestal comprising a filling of refractory concrete next adjacent the inner side of said band, and said band having vertical corrugations to permit the band to yield outwardly on cooling by flattening of the corrugations under radial stress applied to the inner side of the band by spall of the like foreign matter which has found its way between said band and pedestal during thermal expansion of said band.

2. A charge support for a furnace base comprising a generally cir ular refractory pedestal on the base, a metal plate forming a protective for the top of the pedestal, a metal band ounding and embracing the pedestal toform a protective outside wall therefor, said pedestal comprising a filling of refractory concrete next adjacent the inner side of said hand, said band having erticai corrugations to permit said band to yield outwardly on cooling by flattening of the corrugations under radial stress applied to the inner side of the band by the spall and the like which has found its way between said band and pedestal during thermal expansion or" said band, and means for securing the upper edge of said and to said plate at peripherally spaced points along said band.

THEODORE W. MUN'FORD.

REFERENCES QHED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,028,106 Otis Jan. 14, 1936 2,059,029 Williams Aug. i, 1936 2,233,530 Breedon et a1. l Mar. lii ll 2,479,192 Dailey, Jr Aug. 16, 1946 

